Many types of power turf mowing equipment are known. Such equipment can generally be classified by the type of cutting unit the particular mower employs. A rotary cutting unit includes one or more rigid steel blades rotated about a vertical axis within a housing or "cutting deck." The blades cut the grass at a predetermined height above the ground. On the other hand, a reel cutting unit includes a frame within which is mounted a rotating reel having a plurality of arcuate blades, the reel rotating about a generally horizontal axis. The rotating reel blades pass in close proximity to a bedknife which spans the cutting unit frame parallel to the reel axis. Grass is sheared as it passes between the reel blade and bedknife. While rotary cutting units are suitable for many purposes, it is generally perceived that reel cutting units provide a more precise cut. The present invention relates to reel-type mowers and the remainder of this discussion will focus accordingly.
Power turf mowing equipment can also be categorized based on the method used to propel the cutting units. Generally, there are walk-behind, riding, and towed turf mowers. The present invention relates primarily to riding turf mowers and specifically, those riding turf mowers with three reel-type cutting units, generally referred to as triplex mowers.
Triplex mowers typically include a traction vehicle supported by a plurality of wheels, including one or more traction wheels; a prime mover supported by the vehicle frame and connected through a transmission to the traction wheel(s); and three cutting units powered by the prime mover, two units mounted generally ahead of the front wheel(s) and laterally offset about the longitudinal or fore-and-aft axis of the vehicle, and one unit mounted generally between the front and rear wheels and centered about the vehicle longitudinal axis. Typically, the two forward cutting units of a triplex mower are symmetrically offset about the longitudinal axis of the traction vehicle, leaving an uncut section therebetween during operation. Being centered about the longitudinal axis of the vehicle, the rear cutting unit then spans the uncut section and overlaps the mowed path of both forward units. Consistent mowing across the full span of the cutting units is thus obtained. When not cutting, the mower typically has the ability to raise the cutting units to a "transport" position.
Triplex turf mowers can further be differentiated by the particular mowing task they perform. A greens mower is generally a small, maneuverable mower with high-precision cutting units suitable for maintaining golf greens. These mowers often include a grass collection system to collect clippings. A second type of turf mower is the fairway mower. Reel-type fairway mowers are generally larger that greens mowers and often include five or more cutting units (e.g., "5-plex" mowers) for a wider mowed path. Finally, a trim mower is similar in size to the greens mower but is designed specifically to mow around tees and turf boundaries, e.g., around greens, sandtraps, and water.
The trim mower differs from the greens mower in other respects as well. For example, the greens mower is designed to provide a high precision cut on relatively flat, smooth turf. The trim mower, however, while slightly sacrificing quality of cut, can mow irregular turf such as intermediate roughs and inclines. The tires of the two mowers also differ. In order to traverse irregular turf, the tires of the trim mower must have adequate tread to ensure traction. The tires of the greens mower, on the other hand, usually have minimal tread in order to reduce possible damage to the green. Additionally, because of the more precise cut required of the greens mower, it typically operates at lower vehicle velocities than the trim mower. Thus, the trim mower and the greens mower, while similar in some respects, are each designed to address separate turf maintenance needs.
The present invention, as previously stated, is directed specifically to triplex trim mowers. Like the greens mower, the trim mower must be highly maneuverable to permit operation around irregular boundaries. Additionally, the overall cutting width of the trim mower must remain sufficiently narrow to permit passage between course impediments, e.g., landscaping and trees. As such, the front cutting units typically provide minimal lateral extension beyond the outer edge of each front wheel. While this configuration results in a nimble mower, there is a significant drawback. A historical problem with conventional trim mowers is that the operator must necessarily place the front wheel close to the boundary to be mowed. Typically, these boundaries can have sharp drop-offs (i.e., lower elevation) from the turf being mowed. For example, the boundaries of a sand trap are generally several inches below turf level. When mowing around such areas, the operator must ensure that the front wheel of the mower remains on the turf and does not drop over the boundary. That is, the operator must maintain a safe distance between the wheels and the boundary being mowed. Dropping a wheel, in addition to damaging the cutting units, can negatively affect the stability of the mower and possibly endanger the operator. Accordingly, at the completion of the mowing operation, it is often necessary to perform a subsequent trimming operation with either a hand mower or flexible line trimmer. This additional clean-up step is inconvenient and time-consuming.
These problems have been addressed in the past by merely increasing the width of the cutting units, thereby increasing the lateral extension beyond the front wheels. Unfortunately, longer cutting units make the mower wider and less maneuverable. Additionally, the ground-following capability of the cutting unit diminishes with increased length, resulting in uneven cutting. As such, increased cutting unit width has not resolved the issues regarding effective trim mower operation.
Thus, a mower providing increased lateral extension of the cutting units without sacrificing mower maneuverability or performance is highly desirable. The Applicants are aware of several devices that have sought to address this need in the context of non-trim mowers by providing laterally adjustable or laterally offset cutting units. As explained, though, these devices do not adequately address the unique requirements of the trim mower.
There are a number of non-trim mowers designed to laterally extend and retract the cutting unit(s) relative to the support vehicle. Many of these mowers utilize a single, side-mounted cutting unit. This configuration substantially increases mower width and therefore limits maneuverability, an undesirable consequence for a trim mower. For example, U.S. Pat. No. 2,882,978 issued to Smith et al, discloses a selectably slidable, laterally offset mower for trimming beneath overhanging obstacles such as low tree branches. U.S. Pat. No. 4,873,818, issued to Turner, is directed to a similar mower that provides increased offset capability.
Conventional riding mowers with singular, rotary cutting decks that may be laterally displaced relative to the vehicle are also known. For instance, U.S. Pat. No. 4,893,456 issued to Wallace, and U.S. Pat. No. 5,483,789 issued to Gummerson, show a single cutting deck that can be laterally displaced from a conventional centered position to a laterally extended position. However, neither of these inventions describes a method for laterally moving a plurality of separate reel-type cutting units in the context of a triplex trim mower.
Applicants are also aware of towed cutting units capable of lateral displacement relative to the vehicle. U.S. Pat. No. 3,090,184 to Hadek shows a towed gang mower wherein the central mowers move laterally relative to the rest of the gang. In U.S. Pat. No. 3,893,283 to Dandl, a towed gang of two cutting units is described wherein a trailing unit is pivotally mounted to a forward unit. The trailing unit may be selectively positioned about the latter to laterally displace the mowed path. However, the forward cutting unit remains fixed relative to the vehicle at all times.
Lastly, U.S. Pat. No. 4,866,917, issued to Phillips et al, discloses a triplex greens mower with a fixed offset reel arrangement. This particular mower is directed to the unique requirements of greens mowers. Typical greens maintenance involves an outer perimeter cut followed or preceded by parallel back-and-forth cuts over the remainder of the green. In the past, the perimeter cut required the mower to traverse roughly the same cutting path each time. As a result, some believe that compaction of the green may have occurred due to the repeated passing of the vehicle wheels over the same path. By providing an offset reel configuration, the Phillips invention allegedly allows the operator to reduce turf compaction by merely alternating the direction of the subsequent perimeter cut. Since the cut path is laterally offset from the wheel base, switching directions causes the wheels to follow a different path for the same cut. While potentially commendable in eliminating compaction of greens, the fixed relationship of the reels in the Phillips invention is not necessarily beneficial to trim mowers. For example, such a mower would be forced to traverse trim boundaries in a uniform direction to take advantage of the fixed offset cutting units. Due to the irregular nature and occurrence of obstructions encountered during trim mower operation, a fixed offset reel arrangement serves little if any benefit.
Thus, there is an unmet need for an improved mower that incorporates the superior cutting performance and maneuverability of the triplex trim mower with the ability to operate safely and effectively near trim boundaries. The triplex mower of the present invention addresses this problem.